title: Probing the enantioselectivity of a diverse group of purified cobalt-centred nitrile hydratases.
abstract: In this study a diverse range of purified cobalt containing nitrile hydratases (NHases, EC 4.2.1.84) from Rhodopseudomonas palustris HaA2 (HaA2), Rhodopseudomonas palustris CGA009 (009), Sinorhizobium meliloti 1021 (1021), and Nitriliruptor alkaliphilus (iso2), were screened for the first time for their enantioselectivity towards a broad range of chiral nitriles. Enantiomeric ratios of >100 were found for the NHases from HaA2 and CGA009 on 2-phenylpropionitrile. In contrast, the Fe-containing NHase from the well-characterized Rhodococcus erythropolis AJ270 (AJ270) was practically aselective with a range of different α-phenylacetonitriles. In general, at least one bulky group in close proximity to the α-position of the chiral nitriles seemed to be necessary for enantioselectivity with all NHases tested. Nitrile groups attached to a quaternary carbon atom were only reluctantly accepted and showed no selectivity. Enantiomeric ratios of 80 and >100 for AJ270 and iso2, respectively, were found for the pharmaceutical intermediate naproxennitrile, and 3-(1-cyanoethyl)benzoic acid was hydrated to the corresponding amide by iso2 with an enantiomeric ratio of >100.
authors.affiliation: Biocatalysis & Organic Chemistry, Department of Biotechnology, Delft University of Technology, Julianalaan 136, 2628 BL, Delft, The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: van Pelt
authors.forename: M
authors.initials: M
authors.lastname: Zhang
authors.forename: L G
authors.initials: LG
authors.lastname: Otten
authors.forename: J
authors.initials: J
authors.lastname: Holt
authors.forename: D Y
authors.initials: DY
authors.lastname: Sorokin
authors.forename: F
authors.initials: F
authors.lastname: van Rantwijk
authors.forename: G W
authors.initials: GW
authors.lastname: Black
authors.forename: J J
authors.initials: JJ
authors.lastname: Perry
authors.forename: R A
authors.initials: RA
authors.lastname: Sheldon
mesh_terms: D000097:Acetonitriles / Q000737:chemistry* / Q000378:metabolism; D039903:Actinobacteria / Q000201:enzymology*; D006836:Hydro-Lyases / Q000302:isolation & purification / Q000378:metabolism*; D012241:Rhodopseudomonas / Q000201:enzymology*; D016962:Sinorhizobium meliloti / Q000201:enzymology*; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D000097:Acetonitriles; C006725:benzyl cyanide; D006836:Hydro-Lyases; C048831:nitrile hydratase